Package pygeodesy :: Module geoids :: Class GeoidPGM |
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# Class GeoidPGM

         object --+
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       named._Named --+
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    heights._HeightBase --+
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                 _GeoidBase --+
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                             GeoidPGM

Geoid height interpolator for Karney's GeographicLib Earth Gravitational Model (EGM) geoid egm*.pgm datasets but based on `SciPy` RectBivariateSpline or interp2d interpolation.

Use any of the egm84-, egm96- or egm2008-*.pgm datasets. However, unless cropped, an entire `egm*.pgm` dataset is loaded into the `SciPy` RectBivariateSpline or interp2d interpolator and converted from 2-byte `int` to 8-byte `dtype float64`. Therefore, internal memory usage is 4x the egm*.pgm file size and may exceed the available memory, especially with 32-bit Python, see properties `.nBytes` and `.sizeB`.

Instance Methods
__init__(self, egm_pgm, crop=None, datum=None, kind=3, name='', smooth=0) New GeoidPGM interpolator. |
__call__(self, *llis) Interpolate the geoid height for one or several locations. |
height(self, lats, lons) Interpolate the geoid height for one or several lat-/longitudes. |
Inherited from `_GeoidBase`: `__enter__`, `__exit__`, `__repr__`, `__str__`, `center`, `close`, `highest`, `loweright`, `lowerleft`, `lowerright`, `lowest`, `outside`, `toStr`, `upperleft`, `upperright` Inherited from `named._Named`: `__imatmul__`, `__matmul__`, `__rmatmul__`, `attrs`, `classof`, `copy`, `dup`, `methodname`, `rename`, `toRepr`, `toStr2` Inherited from `object`: `__delattr__`, `__format__`, `__getattribute__`, `__hash__`, `__new__`, `__reduce__`, `__reduce_ex__`, `__setattr__`, `__sizeof__`, `__subclasshook__`

Properties
Inherited from `_GeoidBase`: `closed`, `cropped`, `dtype`, `endian`, `hits`, `kind`, `knots`, `mean`, `nBytes`, `name`, `pgm`, `sizeB`, `smooth`, `stdev`, `u2B` Inherited from `heights._HeightBase`: `adjust`, `datum`, `kmin`, `numpy`, `scipy`, `scipy_interpolate`, `wrap` Inherited from `named._Named`: `classname`, `classnaming`, `iteration`, `named`, `named2`, `named3`, `named4` Inherited from `object`: `__class__`

Method Details

### __init__ (self, egm_pgm, crop=None, datum=None, kind=3, name='', smooth=0) (Constructor) |
New GeoidPGM interpolator. Arguments: `egm_pgm` - An EGM geoid dataset file name (`egm*.pgm`). `crop` - Optional box to crop `egm_pgm`, a 4-tuple (`south, west, north, east`) or 2-tuple (`(south, west), (north, east)`), in `degrees90` lat- and `degrees180` longitudes or a 2-tuple (`LatLonSW, LatLonNE`) of `LatLon` instances. `datum` - Optional grid datum (Datum, Ellipsoid, Ellipsoid2 or a_f2Tuple), default `WGS84`. `kind` - `scipy.interpolate` order (`int`), use 1..5 for RectBivariateSpline, -2 for interp2d linear, -3 for `interp2d cubic` or -5 for `interp2d quintic`. `name` - Optional geoid name (`str`). `smooth` - Smoothing factor for RectBivariateSpline only (`int`). Raises: `GeoidError` - EGM dataset `egm_pgm` issue or invalid `crop`, `kind` or `smooth`. `ImportError` - Package `numpy` or `scipy` not found or not installed. `LenError` - EGM dataset `egm_pgm` axis mismatch. `SciPyError` - A `RectBivariateSpline` or `inter2d` issue. `SciPyWarning` - A `RectBivariateSpline` or `inter2d` warning as exception. `TypeError` - Invalid `datum`. Overrides: object.__init__ Note: The GeographicLib egm*.pgm file sizes are based on a 2-byte `int` height converted to 8-byte `dtype float64` for `scipy` interpolators. Therefore, internal memory usage is 4 times the `egm*.pgm` file size and may exceed the available memory, especially with 32-bit Python. To reduce memory usage, set keyword argument `crop` to the region of interest. For example `crop=(20, -125, 50, -65)` covers the conterminous US (CONUS), less than 3% of the entire `egm2008-1.pgm` dataset. See Also: Class GeoidKarney and function egmGeoidHeights.

### __call__ (self, *llis) (Call operator) |
Interpolate the geoid height for one or several locations. Arguments: `llis` - The location or locations (`LatLon`, ... or `LatLon`s). Returns: A single interpolated geoid height (`float`) or a list or tuple of interpolated geoid heights (`float`s). Raises: `GeoidError` - Insufficient number of `llis`, an invalid `lli` or the `egm*.pgm` geoid file is closed. `RangeError` - An `lli` is outside this geoid's lat- or longitude range. `SciPyError` - A `scipy.interpolate.inter2d` or `-.RectBivariateSpline` issue. `SciPyWarning` - A `scipy.interpolate.inter2d` or `-.RectBivariateSpline` warning as exception. Overrides: heights._HeightBase.__call__

### height (self, lats, lons) |
Interpolate the geoid height for one or several lat-/longitudes. Arguments: `lats` - Latitude or latitudes (`degrees` or `degrees`s). `lons` - Longitude or longitudes (`degrees` or `degrees`s). Returns: A single interpolated geoid height (`float`) or a list of interpolated geoid heights (`float`s). Raises: `GeoidError` - Insufficient or non-matching number of `lats` and `lons`. `RangeError` - A `lat` or `lon` is outside this geoid's lat- or longitude range. `SciPyError` - A `scipy.interpolate.inter2d` or `-.RectBivariateSpline` issue. `SciPyWarning` - A `scipy.interpolate.inter2d` or `-.RectBivariateSpline` warning as exception. Overrides: _GeoidBase.height